Abstract: The main objective of this paper is to present the modeling and simulation of open loop dynamics of a rigid body insect-like flapping wing. The most important aerodynamic mechanisms that explain the nature of the flapping flight, including added mass, rotational lift and delayed stall, are modeled. Wing flapping kinematics is described using appropriate reference frames and three degree of freedom for each wing with respect to the insect body. In order to simulate nonlinear differential equations of motion, 6DOF model of the insect-like flapping wing is developed, followed by an evaluation of the simulation results in hover condition.
Abstract: The problem of optimal dynamic allocation of resources in security should be built in such a manner to include the impact assessment of rare events, such as natural or asymmetric extreme events. This paper presents a model for the analysis of investment situations that involves real options with multiple sources of jump risk and identification of management solutions that increase the value of the investment opportunity using Wiener processes and Poisson distribution. The results are solutions for improved decision-making in aviation systems.
Abstract: This paper presents the supersonic combustion of hydrogen using strut injector along with two-dimensional turbulent non-premixed combustion model with air inlet temperature of 750 0k and vitiated Mach number of 2. In this process, a PDF approach is created and this method needs solution to a high dimensional PDF transport equation. As the combustion of hydrogen fuel is injected from the strut injector, it is successfully used to model the turbulent reacting flow field. It is observed from the present work that, the maximum temperature of 2096 0k occurred in the recirculation area which is produced due to shock wave-expansion and the fuel jet losses concentration and after passing successively through such areas, temperature decreased slightly along the axis. From the maximum mass fraction of OH, it is observed that there is very little amount of OH around 0.0017 were found out after combustion. By providing strut injector, expansion wave is created which causes the proper mixing between the fuel and air that results in complete combustion.
Abstract: In resent years, due to advances in science technology, space satellites have made progress. So, the presence of space debris has become problem in the world because they may collide each other. In our study, we have developed Spherical Ultrasonic Motor (SUSM) for space use with 3 DOF to drive the satellite thruster and resolve it. We aim that the satellites enter the atmosphere when the satellites reached the end of life, and SUSM controls thrusters when they inject for the directional control. We have made experiments of measuring torque, durability and lifetime. It shows that the torque and lifetime meets target value. But durability does not meet target value. To resolve it, we have applied stator lining materials and shifted frequency with 0.4 kHz from resonant frequency and we have shown that it meets durability-required specifications.
Abstract: The purpose of this paper is to present some aspects regarding the computational model and technical solutions for multistage suborbital launcher for testing (SLT) used to test spatial equipment and scientific measurements. The computational model consists in numerical simulation of SLT evolution for different start conditions. The launcher model presented will be with six degrees of freedom (6DOF) and variable mass. The results analysed will be the flight parameters and ballistic performances. The discussions area will focus around the technical possibility to realize a small multi-stage launcher, by recycling military rocket motors. From technical point of view, the paper is focused on national project “Suborbital Launcher for Testing” (SLT), which is based on hybrid propulsion and control systems, obtained through an original design. Therefore, while classical suborbital sounding rockets are unguided and they use as propulsion solid fuel motor having an uncontrolled ballistic flight, SLT project is introducing a different approach, by proposing the creation of a guided suborbital launcher, which is basically a satellite launcher at a smaller scale, containing its main subsystems. This is why the project itself can be considered an intermediary step in the development of a wider range of launching systems based on hybrid propulsion technology, which may have a major impact in the future European launchers programs. SLT project, as it is shown in the title, has two major objectives: first, a short term objective, which consists in obtaining a suborbital launching system which will be able to go into service in a predictable period of time, and a long term objective that consists in the development and testing of some unconventional sub-systems which will be integrated later in the satellite launcher as a part of the European space program. This is why the technical content of the project must be carried out beyond the range of the existing suborbital vehicle programs towards the current technological necessities in the space field, especially the European one.
Abstract: This paper presents the development of two different control techniques as an approach having to remove steady-state error present in the response of attitude of a mini unmanned aerial vehicle of four rotor model. The Bessel approximation allows the selection of the eigenvalues in function to a specified response time for a feedback pole placement controller and state estimator. On the other hand presents an optimal control technique combined with Kalman filter to estimate the state affected by perturbations in the system, both cases using the integral effect to eliminate the steady state error.
Abstract: A series of conflicting requirements to which the design of the compound rocket motors are subjected are considerably diminishing the efficiency of that type of rocket motors. The necessity of delivering a high thrust level at lift-off and during the sustainer phase up to optimal velocity accommodation, coupled with the requirement for a slander body configuration for air drag mitigation during the atmospheric ascent are the dominant issues that end into a compromise that lower the overall efficiency to a great extent, in comparison the available theoretical performance of compound rocket motors. The optimal design is imposing a lower mass ratio that expected and is the main cause of efficiency reduction when very high velocity requirements are searched for, like in orbital launchers. However, the margins of propulsive efficiency build-up can be conveniently manipulated through geometrical optimization and attentive risk management of the propulsion system as shown by the experimental results protruded during the development of the NERVA-ORVEAL space rocket motor.
Abstract: This paper presents a Kalman type method for attitude determination of satellites. It is shown that the linearized model describing the satellite kinematics may be expressed as a stochastic system corrupted with both additive and multiplicative white noise. For this class of stochastic models a hybrid Kalman filter is used to estimate the quaternion expressing the satellite attitude and the bias of the inertial measurement unit. By contrast with the classical Kalman filters, the hybrid filter used in this paper includes a continuous-time and a discrete-time component. The advantage is that it may provide a time varying estimation of the states between the sampling moments which usually are sparse in space applications. The theoretical developments is illustrated via a numerical case study.
Abstract: This paper presents the activities that define a strategic development plan for a new liquid hydrogen turbopump that will equip a rocket engine and the capabilities of COMOTI Romanian Research and Development Institute for Gas Turbines in order to develop such type of product. The paper highlights the design, assembly and manufacturing stages for the two main components of a turbopump, the pump and the turbine. Subjected to analysis are the constructive solutions, performances, software for hydraulic, gasodynamic and stress calculus, and also the manufacturing technologies.